That's the right approach. Building from real use keeps you honest about what actually matters vs what sounds cool in a feature list. Good luck with the launch.
The best tools come from scratching your own itch. 2000 photos is exactly the kind of pain point that no existing tool solves well enough because the big players optimize for the casual user, not the power user with a specific workflow. I built a CLI tool for the same reason — existing solutions didn't work the way I needed them to. Curious: are you planning to ship this or keep it as a personal tool?
The PowerPC-to-Intel transition still has the cleanest binary-format story in mainstream consumer OS history — Rosetta 1 was better engineering than people remember. Wild to see the Wii hardware resurrected for this.